The investigators propose to determine the nucleotide sequence of the genome of Streptococcus sanguis. This member of the human indigenous oral microflora has long been recognized as a key player in the bacterial colonization of the mouth. It directly binds to oral surfaces and serves as a tether for the attachment of a variety of other oral microorganisms which colonize the tooth surface, form dental plaque, and contribute to the etiology of both caries and periodontal disease. Furthermore, S. sanguis has been long recognized as a leading cause of bacterial endocarditis, a disease of high morbidity which is fatal if untreated. Moreover, S. sanguis and other viridans streptococci of the mouth are emerging as life-threatening bloodstream pathogens in neutropenic patients. And such infections are being compounded by the increasing frequency with which penicillin resistance is being observed in this group of organisms. New knowledge about this organism could be used in controlling oral microbial colonization so as to minimize or eliminate plaque-related oral diseases. Since the mouth is the source of S. sanguis isolates that cause endocarditis and bacteremia, novel controlling strategies also would have an impact on systemic infections. S. sanguis genomic data will provide new insights into this organism's lifestyle and virulence properties that cannot be extrapolated from analyzing the genomic data of even closely related species. The investigators believe that the complete genomic structure of S. sanguis is certain to lead to the discovery of new genes, insights into their regulation, and an appreciation of their interactions at both the genotypic and phenotypic levels. This, in turn, will provide researchers with new targets for vaccines and rationally designed drugs.